Optical design of a cooled mid-wave infrared off-axis three-mirror system with a low F-number and wide field of view

Xie, Yongming; Liu, Chunyu; Liu, Shuai; Xu, Minglin; Fan, Xinghao; Rao, Qilong

doi:10.1364/ao.449841

Cited by 4 publications

(1 citation statement)

References 27 publications

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“…During the coaxial design phase, the quaternary mirror (QM) contributes very little to the overall optical power of the system, and can even be a flat mirror without optical power. Therefore, an initial Cassegrain-style three-mirror configuration with a relay image can adequately satisfy the design requirements [33][34][35][36]. Figure 6 shows a ray tracing of an on-axis Cassegrain design for the TianQin mission, including a real relay image.…”

Section: Coaxial System Designmentioning

confidence: 99%

Pupil aberrations correction of the afocal telescope for the TianQin project

Fan

Zhu

et al. 2023

Class. Quantum Grav.

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TianQin is a planned Chinese space-based gravitational wave (GW) observatory with a frequency band of 10-4 to 1Hz. Optical telescopes are essential for the delivery of the measurement beam to support a precise distance measurement between pairs of proof masses. As the design is driven by the interferometric displacement sensitivity requirements, the stability control of optical path length (OPL) is extremely important beyond the traditional requirement of diffraction-limited imaging quality. In a telescope system, the recurring tilt-to-length (TTL) coupling noise arises from the OPL variation due to the wavefront deformation and angular misalignment. Reducing the residual chief ray aberration in the optical design helps suppress TTL coupling noise. To correct the pupil aberrations, we derive primary pupil aberrations in a series expansion form, and then refine the formulation of merit function by combining the pupil aberration theory and traditional image aberration theory. The automatic correction of pupil aberrations is carried out by using the macro programming in the commercial optical software Zemax, leading to a high performance telescope design. The design results show that on one side the pupil aberrations have been corrected, and on the other side, its optical performance meets the requirements for TianQin project. The RMS wavefront error over the science field of view (FOV) is less than λ/200 and the maximum TTL coupling noise over the entire ±300 μrad FOV is 0.0034nm/µrad. We believe that our design approach can be a good guide for the space telescope design in any other space-based GW detection project, as well as other similar optical systems.

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Section: Coaxial System Designmentioning

confidence: 99%

Pupil aberrations correction of the afocal telescope for the TianQin project

Fan

Zhu

et al. 2023

Class. Quantum Grav.

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Design of a free-form off-axis three-mirror optical system with a low f-number based on the same substrate

Sun

Chen

et al. 2022

Appl. Opt.

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In this paper, we design a free-form off-axis three-mirror optical system with a low f -number and compact structure, which can be used as an infrared reflection imager. The initial structure is calculated from the near-axis optical transfer matrix based on third-order aberration theory. Particular constraints are designed to install all mirrors on the same substrate for simultaneous milling, which reduces the processing difficulty and effectively avoids errors caused by component assembly. Zernike free-form surfaces are introduced to correct aberrations. This optical system has a field of view of 5 ∘ × 5 ∘ and an f -number of 1.82; the modulation transfer function of the system is higher than 0.6 at 30 lp/mm. The results of the tolerance assignment of the system were verified by the Monte Carlo method, and the machining tolerance is reasonable and easy to achieve. This design not only improves the optical performance of the system but also enhances the feasibility of manufacturing.

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Cooled infrared coaxial four-mirror system design with a low F-number

Zhang¹,

Liu²,

Wang³

et al. 2023

Appl. Opt.

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A low F-number and 100% cold stop efficiency are beneficial for improving the performance of optical systems and have a wide range of applications in various thermal imaging scenarios. The cooled infrared coaxial four-mirror system can meet these two requirements, improve system integration, and reduce adjustment costs and difficulties. However, the secondary obstruction caused by the central hole of the third mirror will generate potential stray light. A structure model is proposed in which the primary mirror and the quaternary mirror are processed on the same mirror blank. In this model, a method is given to calculate system parameters using the obstruction ratio and magnification of each mirror. To evaluate the performance of the method, two design examples with different F-numbers (1.4, 1.0) were constructed. The influence of initial structural constraints on the exit pupil position and secondary obstruction was analyzed based on the design objectives of the examples. The aberrations were optimized by targeting the spot. In the optimization process, the incident coordinates and directions of the restricted edge field rays in the tertiary mirror and the quaternary mirror were limited to achieve control of the obstruction caused by the holes in the center of the mirrors. In the results, the RMS spot radius of the two design examples is smaller than the Airy disk radius, and the axial beam wavefront deviation RMS values are 0.026λ and 0.024λ, respectively. Moreover, the obstruction caused by the central holes of the mirrors is controlled within the given field of view. The results show that the proposed model and method can be used to design a low F-number cooled infrared coaxial four-mirror system and have good application prospects.

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Optical design of a cooled mid-wave infrared off-axis three-mirror system with a low F-number and wide field of view

Cited by 4 publications

References 27 publications

Pupil aberrations correction of the afocal telescope for the TianQin project

Pupil aberrations correction of the afocal telescope for the TianQin project

Design of a free-form off-axis three-mirror optical system with a low f-number based on the same substrate

Cooled infrared coaxial four-mirror system design with a low F-number

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